Catheter system with magnetic coupling

ABSTRACT

A robotic catheter system including a first drive mechanism comprising a drive which interacts with a catheter device to cause the catheter device to move along its axis. A first encoder assembly that detects the motion of the catheter device by a magnetic interaction with the catheter device.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/790,272 entitled CATHETER SYSTEM WITH MAGNETIC COUPLING filed Mar.15, 2013 and incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of robotic cathetersystems for performing interventional procedures. One interventionalprocedure used to treat patients with diseased, often obstructed, heartarteries, is a percutaneous coronary intervention (“PCI”).

Before performing an interventional procedure with the disclosedinvention, a diagnostic procedure is typically performed. An exemplarydiagnostic procedure performed before performing a PCI may include anumber of steps. Starting in the femoral artery, a 0.038 guide wire isrun over the top of the aortic arch. A diagnostic catheter is advancedover the 0.038 guide wire after which the 0.038 guide wire is removedallowing the diagnostic catheter (DC) to return to its preformed shapeenabling the DC to access either the left or the right ostium of theaorta. A contrast media is injected through the DC and the heart isx-rayed to identify the existence and location of any lesion. Ay-connector may be secured to the end of the DC outside of the patient.The y-connector provides a means for introducing the contrast media ormedication. The y-connector employs a one way valve both at they-connector leg and the free open end. The 0.038 guide is thenreinserted into the DC advanced over the top of the aortic arch, and thediagnostic catheter is removed. When the diagnostic is completed the0.038 guide wire may be left in place for use in a PCI procedure.

SUMMARY OF THE INVENTION

One embodiment relates to a robotic catheter system with a drivemechanism comprising a drive wheel, mounted on a hub, which interactswith a catheter device to cause the device to move along its axis and inwhich the mechanism has a magnetic interaction with this catheterdevice. Another embodiment relates to robotic catheter system with afirst drive mechanism comprising a drive wheel mounted on a hub whichinteracts with the first catheter device to cause this device to movealong its axis, a first encoder assembly which detects the motion of thefirst catheter device and has a wheel, mounted on a hub, that is drivenby interaction with the first catheter device, a second drive mechanismcomprising a drive wheel, mounted on a hub, which interacts with thesecond catheter device to cause this device to move along its axis and asecond encoder assembly which detects the motion of the second catheterdevice and has a wheel mounted on a hub that is driven by interactionwith the first catheter device wherein at least one of the four wheelshas a magnetic interaction with the catheter device with which itinteracts. Another embodiment relates to a robotic catheter system witha first drive mechanism comprising a drive wheel, mounted on a hub,which interacts with the first catheter device to cause the device tomove along its axis, a first encoder assembly which detects the motionof the first catheter device, a second drive mechanism comprising adrive wheel, mounted on a hub, which interacts with the second catheterdevice to cause the device to move along its axis and a second encoderassembly which detects the motion of the second catheter device whereinat least one of the encoder assemblies detects the motion of thecatheter device which it monitors by a magnetic interaction with itscatheter device. A further embodiment relates to a robotic cathetersystem having a first drive mechanism comprising a drive wheel, mountedon a hub, which interacts with the first catheter device to cause it tomove along its axis, a first encoder assembly which detects the motionof the first catheter device, a second drive mechanism comprising adrive wheel, mounted on a hub, which interacts with the second catheterdevice to cause the device to move along its axis, a second encoderassembly which detects the motion of the second catheter device and anarcuate channel which guides the second catheter device after its exit,when moving in a forward direction, from the second drive mechanism,wherein the second catheter device is drawn against the wall of thechannel with the smaller arc by a magnetic interaction. A furtherembodiment includes a 6. A robotic catheter system including a firstdrive mechanism comprising a drive wheel, mounted on a hub, whichinteracts a catheter device to cause the device to move along its axis.A first encoder assembly that detects the motion of the catheter deviceby a magnetic interaction with the catheter device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the robotic vascular catheter system.

FIG. 2 is a perspective view of the bedside system.

FIG. 2A is the bedside system of FIG. 2 with the cassette lid in an openposition.

FIG. 3 is a perspective view of the bedside system with the cassetteremoved from the motor drive base.

FIG. 3A is a perspective view of the bottom of the cassette removed fromthe motor drive base.

FIG. 4 is a view of a heart.

FIG. 5 is a view illustrating the guide catheter, the guide wire, andthe balloon catheter within the heart.

FIG. 6 is a top view of the cassette.

FIG. 7 is a cross section of the cassette when the y-connector is securetaken generally along line 7-7.

FIG. 8 is a cross section of the cassette as shown in FIG. 7 when they-connector is released.

FIG. 9 is a perspective view of a portion of the cassette illustratingthe rotational and axial drive systems.

FIG. 10 is a cross sectional view of the axial drive system.

FIG. 11 is a cross sectional view of the rotational drive takengenerally about line 11-11 of FIG. 6.

FIG. 12 is an alternative embodiment of a cassette system.

FIG. 13 is a perspective view of a portion of the cassette with aguiding catheter support shown in FIG. 3.

FIG. 14 is a perspective view of a portion of the cassette with oneembodiment of a rotating assembly.

FIG. 15 is a perspective view of a bedside system showing anotherembodiment of a cassette prior to being attached to the motor drivebase.

FIG. 16 is a perspective view of a bedside system showing the cassetteof FIG. 15 following attachment to the motor drive base.

FIG. 17 is a perspective view of a cassette in the “loading”configuration.

FIG. 18 is a perspective view of a cassette in the “loaded” or “use”configuration.

FIG. 19 is an exploded perspective view of an axial drive assembly of acassette.

FIG. 20 is a bottom perspective view of a cassette showing the baseplate removed.

FIG. 21 is a top view showing the axial drive assembly in the“disengaged” position.

FIG. 22 is a top view showing the axial drive assembly in the “engaged”position.

FIG. 23A is a top perspective view of a rotational drive assembly of acassette showing the engagement structure in broken lines beneath thechassis.

FIG. 23B is a top perspective view of a rotational drive assembly withthe chassis shown in broken lines.

FIG. 24 is a top view of the rotational drive assembly in the “engaged”position.

FIG. 25 is a top view of the rotational drive assembly in the“disengaged” position.

FIG. 26 is a sectional view of the rotational drive assembly takengenerally along line 26-26 in FIG. 18.

FIG. 27 is a sectional view of the axial drive assembly taken generallyalong line 27-27 in FIG. 18.

FIG. 28A shows a rotational drive assembly coupled to a base plate of acassette.

FIG. 28B shows depression of a release button to disconnect therotational drive assembly from the base plate of the cassette.

FIG. 28C shows removal of the rotational drive assembly from the baseplate of the cassette leaving the guide wire in place.

FIG. 29A shows a beam flexure movement gauge.

FIG. 29B shows a pivoting beam movement gauge.

FIG. 29C shows a wheel movement gauge.

FIG. 30 shows a magnetic array in the axial drive assembly.

FIG. 31 is a cross-sectional view of the magnetic array in the axialdrive assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a robotic vascular catheter system 10 is used forperforming interventional procedures, including performing apercutaneous coronary intervention (“PCI”). Discussion will proceedassuming a PCI is being performed. It should be noted, however, oneskilled in the art would recognize that, although the system describedis configured to perform a PCI, it is capable of performing a number ofinterventional procedures with minor adjustments. For more complexprocedures, more than one robotic vascular catheter system 10 may beused.

Robotic vascular catheter system 10 comprises a bedside system 12 andworkstation 14. The bedside system 12 comprises a motor controller, anarticulating arm 18, an arm support 20, a motor drive base 22, acassette 24, and a guide catheter support 26. Guide catheter support maybe part of the cassette or alternatively may be a separate componentthat can be mounted to the cassette. Bedside system 12 is incommunication with workstation 14, allowing signals generated by userinputs to workstation 14 to be transmitted to bedside system 12,controlling the various functions of beside system 12. Bedside system 12also may provide feedback signals to workstation 14. Bedside system 12may be connected to workstation 14 with a wireless connection means (notshown), with cable connectors (not shown), or with any other meanscapable of allowing signals generated by user inputs to workstation 14to be transmitted to beside system 12.

Workstation 14 is capable of being remotely located, enabling roboticvascular catheter system 10 users to perform procedures outside theradiation zone, for instance, in either a procedure room or a separatecontrol room. One benefit of remotely locating workstation 14 is thatthe need to wear heavy lead garments may be eliminated. This reducesorthopedic occupational hazards, including, but not limited to, spinalinjuries and general strain on the body of the operator. A secondbenefit of remotely locating workstation 14 is that the dangersassociated with radiation exposure are reduced. A third benefit ofremotely locating workstation 14 is that it allows users to multitaskoutside the procedure room during downtime.

Bedside system 12 may be coupled to a standard table side bar (notshown) of a patient's bed 28 by locking bedside system 12 relative to apatient 30. The front of bedside system 12, and correspondingly cassette24, is the end nearest the head of patient 30 when a procedure is beingperformed. The back of bedside system 12 is the end opposite the front.Coupling the bedside system to the bed or proximate the patient may beachieved using methods known in the art, including bolting bedsidesystem 12 to the standard table side bar or using any other meanssufficient to lock bedside system 12 relative to patient 30 and/or thebed. Ideally bedside system 12 is secured in a manner that is quick andeasily to install. Bedside system 12 may be permanently coupled to thestandard table side bar throughout numerous procedures, in oneembodiment cassette 24 is replaced for different patients and/ordifferent PCI procedures. However, bedside system 12 may be removablycoupled to a bed for movement from one bed to another.

Cassette 24 is designed for a single use; it is disposable and should bereplaced after each use. Cassette 24 may include a frangible component(not shown) that breaks off when cassette 24 is removed from motor drivebase 22 to help ensure that cassette 24 is used for no more than asingle use. Other mechanical means may be used to ensure a single use.For example, a portion of the cassette may be moved or manipulated in away that does not permit the use of the cassette in another PCIprocedure. Alternatively, cassette 24 may include an RFID (radiofrequency identification) system (not shown) to identify when a cassettehas been used. The cassette may include an RFID tag or other means ofproviding descriptive information identifying the type of cassette,particular features as well as a unique identifier for the particularcassette to distinguish it from any other cassette. Other components orsystems capable of helping ensure that cassette 24 is used for no morethan a single use may also be alternatively used. The fact that cassette24 is designed for a single use has a number of benefits, including, butnot limited to, helping maintain a sterility of robotic vascularcatheter system 10 components and prevent patient-to-patienttransmission of infections. The RFID system may permit the removal ofthe cassette for a short defined period of time, to enable resetting ofthe cassette, if it should fail to be securely attached in the firstinstance. The system could recognize the unique cassette by its uniqueidentification from the RFID signal and allow the same cassette to bereintroduced only within a very short window of time that would suggestthe cassette was being repositioned and not being used for anotherpatient. It is also possible that the cassette may formed from materialsthat can be sterilized and reused, or certain components may be replacedthat come into contact with bodily fluids.

FIG. 2 illustrates a preferred embodiment of robotic vascular cathetersystem 10. Articulating arm 18 is coupled to and protrudes outward fromarm support 20. Motor drive base 22 is coupled to articulating arm 18.Cassette 24 is coupled to the top of motor drive base 22.

Articulating arm 18 is configured to be locked into infinite positionsrelative to patient 30. In a preferred embodiment, articulating arm 18includes a first knuckle 32 and a second knuckle 34. First knuckle 32enables articulating arm 18 to pivot about a vertical axis and or ahorizontal axis. Second knuckle 34 enables articulating arm 18 to pivotup and down or about a horizontal axis. Articulating arm 18 may havemultiple degrees of freedom to position cassette 24 in any orientationrelative to the patient for proper positioning. Once the user hasadjusted articulating arm 18, articulating arm 18 is locked into placeby an articulating arm locking mechanism, preventing unwanted movementduring the procedure. Articulating arm locking mechanism may be lockedand unlocked mechanically, using a solenoid, or using any othermechanism capable of locking articulating arm 18, along with motor drivebase 22 and cassette 24, relative to patient 30.

Referring to FIG. 3, bedside system 12 illustrated in FIG. 2 is shownbefore cassette 24 is attached to motor drive base 22. Motor drive base22 includes a housing 38 and a plurality of capstans 40. Capstans 40extend vertically to facilitate alignment with cassette 24 when couplingmotor drive base 22 and cassette 24. Cassette 24 includes a housing 42,a cover 44 pivotally attached to housing 42, and a plurality of capstansockets 46 corresponding to capstans 40 on motor drive base 22 tofacilitate alignment with motor drive base 22 when coupling cassette 24and motor drive base 22. In one embodiment capstans 40 extend generallyupward and are matingly received in capstan sockets 46 that are locatedon the bottom surface of cassette 24. This permits cassette 24 to beplaced onto motor drive base 22 in a generally downwardly direction. Itis contemplated that motor drive base 22 and cassette 24 will be at anangle relative to a horizontal plane in an operative position to directthe guide catheter, guide wire and working catheter in a downwardlysloping direction toward the patient. Capstans 40 and capstan sockets 46are one embodiment of a motor coupler, coupling the motors to axial androtation drive mechanisms in the cassette. The capstans 40 and capstansockets 46 may have gearing to allow a rotational force to betransmitted from motors located in the motor drive base 22 to the axialand rotational drive mechanisms within the cassette. While the capstansand capstan sockets allow the cassette to be placed downwardly onto themotor drive base, other motor couplers that can couple the motors to thedrive mechanisms are also contemplated. In one embodiment the motors arelocated in the motor drive base 22. However, the motor drive base 22 mayalso be used to transmit force from motors located away from the motordrive base that are operatively coupled to the motor drive base with amechanical linkage such as a cable or other mechanical coupler. It isalso contemplated that the mechanical linkage could directly connect themotors to the capstan sockets so that the motor drive base 22 providessupport for the cassette 24 and permits coupling of the cassette capstansockets to the motors.

As illustrated in FIG. 2A, cover 44 may be opened to provide access tothe mechanisms within cassette 24 to help facilitate loading andunloading of the guide wire and catheter instruments within the cassette24. Cover 44 may include a wall member used to help positively locatethe guide wire within the transmission mechanisms as described morefully below. Cover 44 may be secured by a hinge or other pivot enablingmembers. Alternatively, cover 44 may be secured in an up downarrangement. The movement of cover 44 from a closed to open position maycause the release of the guide wire or other catheter instruments fromthe transmission mechanisms.

Before coupling cassette 24 to motor drive base 22, a sterile, plasticcover (not shown) is draped over articulating arm 18 and motor drivebase 22. The sterile, plastic cover includes pre-cut holes (not shown)that correspond to capstans 40 on motor drive base 22. The sterile,plastic cover shields the sterilized components of robotic vascularcatheter system 10 from the unsterilized components, including motordrive base 22, articulating arm 18, and arm support 20. Cassette 24 issterile before use. Once cassette 24 has been coupled to motor drivebase 22 and used, it is disposed of and replaced with another sterile,single-use cassette.

Referring to FIGS. 6-9, cassette 24 further includes a first axial drivemechanism 48 for driving a guide wire 50 along its longitudinal axis, asecond axial drive mechanism 52 for driving a working catheter 54 alongits longitudinal axis, a first rotational drive mechanism 56 enablingguide wire 50 to rotate while still permitting guide wire 50 to beindependently moved along its longitudinal axis. Working catheter 54 maybe embodied as a balloon, stent on a delivery catheter, a stent with aballoon, or any other therapeutic or diagnostic catheter device; theseembodiments are collectively referred to as working catheter 54. In oneembodiment first axial drive mechanism 48 and first rotational drivemechanism 56 are positioned substantially in series along a longitudinalaxis 60 of cassette 24. In one embodiment, second axial drive mechanism52 is positioned at an angle to first axial drive mechanism 48.

After coupling cassette 24 to motor drive base 22 and before usingrobotic vascular catheter system 10 for a procedure, guide wire 50 andworking catheter 54 must be loaded into the drive mechanisms in cassette24. To load cassette 24, the user opens cover 44. Upon opening cover 44,an engagement-disengagement mechanism is activated, causing the drivemechanisms to automatically adjust for quick access. When cassette 24 isin open cover position, the drive mechanisms are in position for loadingguide wire 50 and working catheter 54. Upon closing cover 44, theengagement-disengagement mechanism is activated, causing the drivemechanisms to automatically adjust, releasably engaging guide wire 50and working catheter 54. Alternatively, it may be possible to engageand/or disengage guide wire 50 when cover 44 is in an open position.When cassette 24 is in closed cover position, the drive mechanisms applysufficient pressure to guide wire 50 and working catheter 54 to be ableto drive them. In a preferred embodiment, cover 44 is formed from aclear, translucent material to permit viewing of the drive mechanismswhile cover 44 is closed, in closed cover position. Though, one of skillin the art would recognize that a variety of other materials aresuitable. It may also be possible to disengage the drive mechanisms witha mechanical switch or electromechanical device with or without firstopening the cover. Disengagement of the drive mechanisms will result inthe surfaces of the pinch rollers of the axial drive mechanisms and theengagement surfaces of the rotational drive mechanism moving away fromone another to allow easy removal and insertion of the guide wire andworking catheter. At least one of the pinch rollers is supported by atleast one disengagement mechanism that physically moves the pinch rollersurfaces away from one another. Similarly, the engagement surfaces ofthe rotational drive mechanism are also operatively connected to adisengagement mechanism to physically move the engagement surfaces ofthe rotational drive mechanism away from one another. The pinch rollersare in a disengagement position when the pinch roller surfaces arepositioned apart from one another.

Cassette 24 further includes a system to self-test the cassette uponloading (not shown). The system for self-testing cassette loading may beactivated by an operator at workstation 14. Alternatively, the systemmay automatically initiate a self-test of the cassette upon closing ofcover 44 to test each of the drive mechanisms. Feedback from the motorsto workstation 14 could confirm proper seating of the cassette withinthe base. In addition to testing that each of the motors are properlysecured to the cassette, each transmission mechanism may be activated tomove the guide wire and/or working catheter a predetermined distance orrotation and then measure the distance actually moved or rotated by useof sensors. If the movement conforms to the predetermined parameters thesystem is shown to be working and operational. When the detectedmovement of the guide wire and/or working catheter does not conform toset parameters the system will show an error message.

Cassette 24 is designed with ergonomic considerations in mind, handle 64enables easy manipulation and movement of the cassette and cassette baseby an operator to position the system relative to the patient. Cover 44may include a latch 210 located on the inside surface of the cover or inwithin the housing of the cassette to hold guide wire 50 duringexchanges or when manipulating more than one wire. Catheter system 10may include system for inflating working catheter 54, and a system forinjecting a contrast media. Specifically, work station 14 may include acontrol mechanism for remotely controlling a pump for the injection of acontrast media.

Referring to FIG. 9 cassette 24 is shown without cover 44 and withouthousing 42. Cassette 24 includes a base plate 70 that supports firstaxial drive mechanism 48 and first rotational drive mechanism 56. Axialdrive mechanism 48 and rotational drive mechanism 56 are positioned andsecured consecutively/in series along a longitudinal axis of base plate70. First axial drive mechanism 48 is shown positioned closer to theback end of cassette 24, behind first rotational drive mechanism 56. Itshould be noted, however, that first rotational drive mechanism 56 maybe positioned behind first axial drive mechanism 48. It is believed thatpositioning rotational drive mechanism 56 closer to the patient providesfor increased control of rotation of the guide wire, since any pressureand/or friction from the rollers in axial drive mechanism 48 is locateddistal the patient.

Referring to FIGS. 9 and 10, first axial drive mechanism 48 includes afirst roller 72 and a second roller 74 working in cooperation to driveguide wire 50 in an axial direction. First roller 72 is spring biasedtoward second roller 74 with sufficient force to provide movement toguide wire 50 upon rotation of rollers 72, 74. It may be possible toadjust the spring force to ensure proper operation of the system. Thespring force is set to allow rotation of guide wire 50 about its axis.In one embodiment first roller 72 has a first engagement surface andsecond roller 74 includes a second engagement surface. Guide wire 50 isremovably placed between the first and second engagement surfaces of thefirst and second rollers 72 and 74 respectively. A solenoid may be usedto move first roller and second roller closer toward and away from oneanother to capture and release guide wire between first and secondrollers 72, 74. A solenoid may be used to move a holder supporting oneof the rollers toward the other roller. A spring on the holder may beemployed to bias one roller toward the other roller to provide asufficient force on the guide wire 50 to effectively permit translationof the guide wire along its longitudinal axis upon rotation of at leastone of the rollers.

Second roller 74 is driven by a drive gear or roller 76 via a belt 78.Sufficient tension is applied to belt 78 via a tension member 80.However, second roller 74 may be driven directly from one of thecapstans 40 in motor drive base 22.

In alternative embodiments, pair of rollers 72, 74 may comprise a rollerand an anvil or a roller and any grip surface wherein the pressurebetween that grip surface and a roller is sufficient to drive guide wire50 along its longitudinal axis.

Further referring to FIGS. 6, 9 and 11, first rotational drive mechanism56 includes a first rotational drive mechanism supporting block 92, asecond rotational drive mechanism supporting block 94, and a rotationaldrive mechanism 96. Rotational drive mechanism 96 includes a plate 100,four pairs of rollers 102, 104, 106, 108, four pairs of roller fasteners110, 112, 114, 116, supported on four pairs of roller axles 118, 120,122, 124, a rotational drive mechanism comb, a longitudinal axis 128,and a pair of cylindrical protrusions 130 that extend through and aresupported in a bore in each of supporting blocks 92 and 94. Pair ofcylindrical protrusions 130, 132 are substantially concentric withrotational drive mechanism 96, extending outward from either end ofrotational drive mechanism 96 along its longitudinal axis 128. Firstrotational drive mechanism supporting block 92 and second rotationaldrive mechanism supporting block 94 are transverse to longitudinal axis128 of base plate 70 and are spaced out along the longitudinal axis ofbase plate 70 a distance sufficient to accommodate rotational drivemechanism 96 between them. Rotational drive mechanism 96 is suspendedand secured between first rotational drive mechanism supporting block 92and second rotational drive mechanism supporting block 94 over baseplate 70 by pair of cylindrical protrusions 130, 132, which also serveas a path for guide wire 50 to extend. Referring to FIG. 14 the elementsof rotational drive mechanism 96 may be supported on a rotating assembly206 that rotates between supporting blocks 92 and 94.

Each supporting block 92, 94 includes a guide wire slit 84 extendingsubstantially radially outward from the longitudinal axis 128 ofrotational drive mechanism 96. Each of the four pairs of rollers 102,104, 106, 108 meets along a longitudinal axis of rotational drivemechanism 96. Four pairs of rollers 102, 104, 106, 108 and four pairs ofroller fasteners 110, 112, 114, 116 are positioned over four pairs ofaxles 118, 120, 122, 124 with four pairs of roller fasteners 110, 112,114, 116 fixing four pairs of rollers 102, 104, 106, 108 along fourpairs of axles 118, 120, 122, 124. While rotational drive mechanism isdescribed with four pair of rollers, it may be possible to use a singlepair of rollers, two or three pair of rollers or more than four pair ofrollers. Referring to FIG. 14 an element 208 is illustrated thatrepresents the path that guide wire 50 would extend through when therotating assembly is in the load and unload position. When the rotatingassembly is in the load and unload position the path represented byelement 208 is in alignment with guide wire slits 84 in supportingblocks 92 and 94 that are illustrated in FIG. 9.

When cover 44 of cassette 24 is in the closed position, a rotationaldrive mechanism locator may be used to assist in the positioning ofguide wire 50 downward toward the longitudinal axis of rotational drivemechanism 96 to help locate and maintain guide wire 50 between the fourpairs of rollers 102, 104, 106, 108. Guide wire 50 is releasably engagedbetween four pairs of rollers 102, 104, 106, 108 in first rotationaldrive mechanism 56. When robotic vascular catheter system 10 is usedduring a procedure, the rollers within the engagement surfaces of thefour pairs of rollers 102, 104, 106, 108 move toward one another toapply sufficient pressure to rotate guide wire 50 upon rotation ofrotational drive mechanism 96 while still permitting guide wire 50 to beindependently moved along its longitudinal axis by axial drive mechanism48. The rotation of guide wire 50 results from the torque imparted onguide wire 50 because of the frictional forces between four pairs ofrollers 102, 104, 106, and 108 during rotation of rotational drivemechanism 96. The rollers in the pairs of rollers 102-108 are free torotate about their vertical axis allowing a guide wire 50 to moveaxially. The pressure between each pair of rollers is sufficient toimpart a rotation to a guide wire 50 located therebetween when theentire rotational drive mechanism is rotated. The rollers may be movedaway from one another to permit easy insertion and removal of guide wire50 to load and unload the guide wire within the rotational drivemechanism. One set of the rollers may be moved away from the other setof rollers when cover 44 is in the open position and allowed to moveback toward the other set of rollers when cover 44 is in a closedposition. In order to easily remove or insert guide wire 50 intorotational drive mechanism 96 between the rollers a vertical path 98must align with guide wire slit 84. When cover 44 is opened, therotational drive mechanism rotates to a load/unload position in whichvertical path 98 is aligned with guide wire slit 84 thereby allowingeasy insertion and/or removal of guide wire 50 from the rotational drivemechanism. In an alternative embodiment, the rollers do not move awayfrom one another but allow for manual insertion and removal of guidewire 50 between the rollers. The manual insertion may be permitted bythe flexibility of the rollers themselves or by permitting one of thespring biased rollers to move away from the second in the pair ofrollers to allow insertion of guide wire 50.

Alternative embodiments of four pairs of rollers 102, 104, 106, 108include, but are not limited to, more or less than four pairs ofrollers. Also, four pairs of rollers 102, 104, 106, 108 comprise pairsof rollers and anvils, each roller paired up with an anvil and creatingsufficient pressure to rotate guide wire 50 upon rotation of rotationaldrive mechanism 96 while still permitting guide wire 50 to beindependently moved along its longitudinal axis. Similarly, four pairsof rollers 102, 104, 106, 108 may alternatively comprise a plurality ofrollers and any grip surface where the pressure between each roller andthat grip surface is sufficient to rotate guide wire 50 upon rotation ofrotational drive mechanism 96 while still permitting guide wire 50 to beindependently moved along its longitudinal axis. In another embodimentrotational drive mechanism may include two engagement surfaces that mayor may not rotate in the axial direction of the longitudinal axis of theguide wire.

When cover 44 of cassette 24 is in open cover position, first axialdrive mechanism 48 and first rotational drive mechanism 56 arepositioned such to facilitate loading guide wire 50 and working catheter54. In the insertion and removal position, guide wire slits 84 insupporting blocks 92, 94 and guide wire path 98 of rotational drivemechanism 96 are substantially aligned. Similarly, pair of rollers 72,74 of first axial drive mechanism 48 and four pairs of rollers 102, 104,106, 108 of first rotational drive mechanism 56 are substantiallyaligned. This enables guide wire 50 to extend through both first axialdrive mechanism 48 and first rotational drive mechanism 56. As discussedabove, each of the pair of rollers in the axial drive mechanism androtational drive mechanism may move apart to facilitate easy insertionand removal of guide wire 50 when cover 44 is in the open position.

Further referring to FIG. 6 second axial drive mechanism 52 comprises apair of rollers 136, and a working catheter channel 138. Pair of rollers136 releasably engage working catheter 54 in working catheter channel138. When cassette 24 is in open cover position, second axial drivemechanism 52 is positioned such to facilitate loading working catheter54 between pair of rollers 136. When cover 44 of cassette 24 is closed,working catheter 54 is loaded and releasably engaged between pair ofrollers 136. Alternate embodiments of second axial drive mechanism 52include, but are not limited to, an embodiment wherein pair of rollers136 comprises a roller and an anvil or a roller and any grip surfacewherein the pressure between that grip surface and a roller issufficient to drive working catheter 54 along its longitudinal axis.Other axial drive mechanisms are also contemplated and may be used.

Referring to FIG. 1 workstation 14 comprises a user interface 142. Userinterface 142 enables a user to enter commands controlling the axialmotion of guide wire 50 via first axial drive mechanism 48, the axialmotion of working catheter 54 via second axial drive mechanism 52, andthe rotational motion of guide wire 50 via first rotational drivemechanism 56. In an alternative embodiment of robotic vascular cathetersystem 10, the user would additionally be capable of controlling a guidecatheter 144 from workstation 14, in an axial and/or rotational manner.

In a preferred embodiment, user interface 142 includes a first screen146 and a second screen 148. First screen 146 and second screen 148 areconfigured to present information and images potentially useful to auser of robotic vascular catheter system 10. User interface 142 furtherincludes a touch screen 150, having a pair of joysticks 152 havingvariable speed control, a first jog button 154 for 1 mm jogs, and asecond jog button 156 for 5 mm jogs. First jog button 154 and second jogbutton 156 have continuous jog capability. Depression of the jog buttonswill move the guide wire 50 a set distance forward. Jog buttons may beused for movement of guide wire 50 and/or working catheter 54.Rotational Jog button may be set to rotate a pre-set degree or it may beset to rotate a selected degree. Another button may be used toaccelerate the speed of the guide wire 50 or provide a multiplier sothat the variable speed control reacts in a heightened manner. Forexample if movement of a joystick a set distance results in the movementof the guide wire at a set speed in normal operation, the guide wirewould move at a multiple of the set speed by depressing the button toaccelerate the speed.

In alternative embodiments, user interface 142 may have variousconfigurations. For instance, touch screen 150 may be integrated withx-ray or other imaging data. In fact, a variety of data and controls maybe integrated on a single screen, including, but not limited to,contrast media insertion control, balloon inflation control, imageprocessing control(s), hemodynamic data, etc. Alternative joystickconfigurations include, but are not limited to separate joysticks may beprovided for each drive mechanism, rather than two joysticks forcontrolling all drive mechanisms.

Robotic vascular catheter system 10 may further incorporate a number ofsafety features and conveniences (not shown). For instance, roboticvascular catheter system 10 may be capable of providing a mechanism fora user to manually override it during a procedure. In the event, thatthe operator must manually align the rotational drive mechanism toremove the guide wire 50, it is contemplated that the rotational drivemechanism can be moved to a load unload position so that the engagementsurfaces in the rotational drive mechanism are separated and in linewith the slits in rotational drive mechanism supports. Additionally,workstation 14 may incorporate a system allowing a user tovoice-activate controls, a feature which could be overridden by anemergency stop. There may also be a force limitation mechanism. Roboticvascular catheter system 10 could have a pre-determined limit to theamount of force that could be placed on guide wire 50. If the motorswere to apply a force greater than the pre-determined amount, a clutchact to disengage the wheels from the motors. For example if any of thedrive mechanisms were to become stuck and unable to rotate a clutchmechanism would act to allow the motors to rotate without causing damageto the stuck drive mechanism or the motor itself.

Another possible feature is a slippage-detecting mechanism. Such amechanism would provide a continuous check between the desired andactual movements of guide wire 50 or working catheter 54 and rollers,pair of rollers 72, 74 of first axial drive mechanism 48 and four pairsof rollers 102, 104, 106, 108 of first rotational drive mechanism 56.This mechanism could provide warnings when a given threshold has beencrossed. This threshold may remain constant throughout a procedure ormay vary depending on the location of system components in the heart. Inone embodiment, an ancillary encoder (not shown) may be used to give theexact location of guide wire 50, in terms of both axial and rotationalmovement, and working catheter 54, in terms of axial movement, during aprocedure. Pair of rollers 72, 74 and four pairs of rollers 102, 104,106, 108 would be positioned near a plurality of idler rollers 158 thatcheck the movement of the robotic vascular catheter system 10, comparingthe movement of the rollers to motor movement. Note that these featuresand conveniences are exemplary and should not be read to be exhaustive.

Referring to FIGS. 3, 7, 8 and 13 in a preferred embodiment cassette 24further includes a coupling mechanism 162 for securing a y-connector 160attached to a guide catheter 144 and a guide catheter support arm, shownas a rod 164. Coupling mechanism 162 releasably secures y-connector 160.Y-connector 160 connects to guide catheter 144. Y-connector 160 furtherprovides a means for administering drugs to a patient during the PCIprocedure. In one embodiment, robotic vascular catheter system 10provides a user the ability to remotely control drug administrationthrough y-connector 160. Guide catheter 144 may be able to pivot aboutits longitudinal axis independent of y-connector 160. The y-connectorincludes three legs. A first leg is attached to the guide catheter 144.A second leg is angled away from the longitudinal axis of the guidecatheter to permit introduction of a contrast agent or medicine. A oneway valve prohibits bodily fluid from exiting the second leg. A thirdleg extends away from the guide catheter and allows insertion of aworking catheter and guide wire through the y-connector. The third legalso includes a one way valve that permits insertion and removal of theworking catheter and guide wire but prohibits bodily fluids from exitingthe third leg.

A rod 164 is coupled to cassette 24 at a point along the front end ofcassette 24 and supports guide catheter support 26 at its other end. Rod164 is adjustable, and capable of translating away from cassette 24 andback towards cassette 24 and moving independently of cassette 24, tohelp position guide catheter 24 using methods known in the art. Inalternative embodiments, rod 164 may take on any number ofconfigurations capable of supporting guide catheter support 26 and guidecatheter 144. For example, guide rod 164 may include telescopingsegments.

Guide catheter support 26, shown as a spring-loaded clamp, providessupport for guide catheter 144. Guide catheter support 26 is at a pointbetween the front end of cassette 24 and patient 30 during a procedure.In this position, guide catheter support 26 helps prevent unwantedmovement of the guide catheter 144 and its contents, affording greateraccuracy when performing a procedure.

Referring to FIG. 6, when guide wire 50 and working catheter 54 havebeen loaded in robotic vascular catheter system 10, cover 44 of cassette24 is closed guide wire 50 extends out of the back end of cassette 24through an opening in housing 42. Moving toward the front end ofcassette 24, guide wire 50 passes through first axial drive mechanism48, through first rotational drive mechanism 56, and then converges withworking catheter 54 at a convergence zone 166. Working catheter 54enters cassette 24 through a slot 168 in the side of housing 42. Beforeconverging with guide wire 50 at convergence zone 166, working catheter54 first passes through second axial drive mechanism 52. Workingcatheter 54 includes a hollow over the wire portion, which guide wire 50passes into at convergence zone 166. Working catheter 54 with guide wire50 in its over the wire portion exits the front end of cassette 24through an opening 172. Cassette 24 may include a channel configured toconstrain the working catheter along a predefined path from a firstpoint where the longitudinal axis of the working catheter and thelongitudinal axis of the guide wire are not coaxial to a point where thelongitudinal axis of the working catheter and the longitudinal axis ofthe guiding catheter are co-axial. The path is located within thehousing and may include a groove or other physical means to form atleast a portion of the path.

Further referring to FIG. 6, y-connector 160 is connected to a proximalend of guide catheter 144. Guide catheter 144 has a central bore. Guidewire 50 and working catheter 54 pass through y-connector 160 intocentral bore 174 of guide catheter 144 upon exiting cassette 24 throughopening 172. In a preferred embodiment, guide catheter 144 runssubstantially parallel to rod 164 from y-connector 160 to guide cathetersupport 26, where it is releasably secured. Guide catheter support 26facilitates movement of guide wire 50 and working catheter 54 withincentral bore 174 of guide catheter 144, by helping to keep guidecatheter 144 straight.

Y-connector 160 is releasably secured to cassette 24 by couplingmechanism 162, shown in a preferred embodiment as a spring-biased clampin FIGS. 7 and 8. Coupling mechanism 162 includes a frame 176, a handle178, and at least one spring 180. Frame 176 includes a receiving portion182 against which y-connector 160 is secured. Handle 178 includes alever arm 184 and a capture portion 186. Capture portion 186 appliessufficient pressure to secure y-connector 160 against receiving portion182 of frame 176 when lever arm 184 is not depressed. Handle 178 pivotsabout a pivot point 188. Springs 180 exert an upward force on lever arm184 at a distance from pivot point 188, biasing capture portion 186 ofhandle 178 toward receiving portion 182 of frame 176. Referring to FIG.8, when lever arm 184 is depressed, springs 180 are also compressed.Capture portion 186 of handle 178 pivots about pivot point 188, movingaway from y-connector 160 and receiving portion 182 and releasingy-connector 160. Referring back to FIG. 7, when handle 178 is releasedlever arm 184 is again forced upward, pivoting about pivot point 188.Capture portion 186 moves in toward receiving portion 182 andy-connector 160, releasably securing y-connector 160.

The exemplary procedure begins after a diagnostic procedure has beencompleted, leaving a diagnostic guide wire (not shown) in a heart 190(shown in FIG. 4), heart 190 including an aorta 192 and an aortic arch194. Before using robotic vascular catheter system 10, guide catheter144 is run up into aorta 192 over the diagnostic guide wire, thediagnostic guide wire is removed, and guide catheter 144 is positionedinto either a right ostium 196 opening to the right coronary artery or aleft ostium 198 opening to the circumflex or left anterior descendingarteries, depending where a lesion 200 is located. The shape of guidecatheter 144 varies based on which ostium it is to enter. As discussedabove, bedside system 12 is likely already fixed to patient's bed 28.

For the purposes of clarity, steps for advancing guide catheter 50 andworking catheter 54 and loading bedside system 12 will be discussedseparately and in turn. One of skill in the art would recognize that anumber of the steps in the discussion are interchangeable withoutdeviating significantly from the method.

Guide catheter 144 is attached to y-connector 160. A y-connectorintroducer (not shown) is placed into y-connector 160. Guide wire 50 isadvanced through the y-connector introducer into guide catheter 144 andthen removed. Working catheter 54 is loaded onto guide wire 50. Workingcatheter 54 is then manually advanced up into guide catheter 144 overguide wire 50 until it is near the free end of guide wire 50.

Cassette 24 is coupled to motor drive base 22 over the sterile, plasticcover. Articulating arm 18 is locked relative to patient 30 and cover 44of cassette 24 is opened, activating engagement-disengagement mechanism,which causes the drive mechanisms to position for loading guide wire 50and working catheter 54. Guide wire 50 is positioned into guide wirepath 98 between four pairs of rollers 102, 104, 106, 108 of firstrotational drive mechanism 56, and into guide wire slit 84 and pair ofrollers 72, 74 of first axial drive mechanism 48. The back end of guidewire 50 extends outwardly through the back of housing 42 and may containa guide wire holder or support to contain the length of guide wire notbeing used within the patient. Working catheter 54 is placed in workingcatheter channel 138 between pair of rollers 136 of second axial drivemechanism 52. After positioning guide wire 50 and working catheter 54,cover 44 of cassette 24 is closed, again activating theengagement-disengagement mechanism. Robotic vascular catheter system 10is loaded, drive mechanisms having releasably engaged guide wire 50 andworking catheter 54.

Y-connector 160 is releasably secured to cassette 24 by depressinghandle 178, placing y-connector 160 between frame 176 and handle 178. Inthis manner guide catheter 144 is releasably secured to the cassette 24.

The user operates the controls at workstation 14. In the above-discussedpreferred embodiment of workstation 14, touch screen 150, a pair ofjoysticks 152, a first jog button 154, and a second jog button 156 areoperated to direct the motion of guide wire 50 and working catheter 54.As shown in FIG. 5, guide wire 50 is typically moved and then followedby working catheter 54 until guide wire 50 is moved across lesion 200.Once guide wire 50 has crossed lesion 200, working catheter 54 is drivenacross, often fine tuning the position using first jog button 154,second jog button 156, or a combination of both.

Referring to FIG. 12, an alternative axial drive 212 member may be used.For example pinch rollers may be replaced with a two belt mechanism.

Referring to FIG. 13, cassette 24 includes a guide catheter support 202.Y-connector coupling mechanism is supported by guide catheter support202. In an alternative embodiment, guide catheter support 202 mayinclude a sled 204 that can be moved in a fore aft direction so that theguide catheter may be moved in a direction along its longitudinal axis.Cassette 24 may also include a drive mechanism to rotate sled 204 suchthat the guide catheter is rotated about its longitudinal axis, and adrive mechanism to move sled 204 in the fore aft direction such that theguide catheter may be moved along the longitudinal axis of the guidewire. The drive mechanisms used to move sled 204 may be located in themotor drive base 22 and move the sled 204 relative to cassette 24, sothat sled 204 may be moved independently of the guide wire and/orworking catheter.

Referring now to FIGS. 15 through 28C, another exemplary embodiment of acassette for use with a robotic catheter system is shown. Similar to theembodiment discussed above, cassette 300 may be equipped with a guidewire 301 and a working catheter 303 to allow a user to perform acatheterization procedure utilizing cassette 300. In this embodiment,bedside system 12 includes a cassette 300 configured to be mounted to amotor drive base 302. FIG. 15 shows a bottom perspective view ofcassette 300 prior to mounting to motor drive base 302. Motor drive base302 includes a first capstan 304, a second capstan 306, and a thirdcapstan 308, and cassette 300 includes a first capstan socket 310, asecond capstan socket 312, and a third capstan socket 314. Cassette 300includes a housing 316, and housing 316 includes a base plate 318.

Each of the capstan sockets is configured to receive one of the capstansof motor drive base 302. In the embodiment shown, base plate 318includes a hole or aperture aligned with each of the capstan sockets310, 312, and 314 to allow each capstan to engage with the appropriatecapstan socket. The engagement between the capstans and capstan socketsallows the transfer of energy (e.g., rotational movement) generated byone or more actuators (e.g., motors) located within motor drive base 302to each of the drive mechanisms (discussed below) within cassette 300.In one embodiment, a single actuator provides energy to each of thedrive mechanisms. In another embodiment, there is an actuator thatdrives capstan 304, an actuator that drives capstan 306, and an actuatorthat drives capstan 308. Further, the positioning of the capstans andcapstan sockets helps the user to align cassette 300 relative to motordrive base 302 by allowing cassette 300 to be mounted to motor drivebase 302 only when all three capstan sockets are aligned with the propercapstan.

In one embodiment, the motors that drive capstans 304, 306, and 308 arelocated within motor drive base 302. In another embodiment, the motorsthat drive capstans 304, 306, and 308 may be located outside of base 302connected to cassette 300 via an appropriate transmission device (e.g.,shaft, cable, etc.). In yet another embodiment, cassette 300 includesmotors located within the housing of cassette 300. In anotherembodiment, cassette 300 does not include capstan sockets 310, 312, and314, but includes an alternative mechanism for transferring energy(e.g., rotational motion) from an actuator external to the cassette toeach of the cassette drive mechanisms. For example, rotational movementmay be transferred to the drive mechanisms of cassette 300 viaalternating or rotating magnets or magnetic fields located within motordrive base 302.

In the embodiment shown, cassette 300 also includes a guide cathetersupport 311 that supports guide catheter 317 at a position spaced fromcassette 300. As shown, guide catheter support 311 is attached tocassette 300 by a rod 313. Rod 313 and guide catheter support 311 arestrong enough to support guide catheter 317 without buckling. Guidecatheter support 311 supports guide catheter 317 at a position spacedfrom the cassette, between the patient and the cassette to preventbuckling, bending, etc. of the portion of guide catheter 317 between thecassette and the patient.

Referring to FIG. 16, cassette 300 is shown mounted to motor drive base302. As shown in FIG. 16, cassette 300 includes an outer cassette cover320 that may be attached to housing 316. When attached to housing 316,outer cassette cover 320 is positioned over and covers each of the drivemechanisms of cassette 300. By covering the drive assemblies of cassette300, outer cassette cover 320 acts to prevent accidental contact withthe drive mechanisms of cassette 300 while in use.

Referring to FIG. 17, cassette 300 is shown in the “loading”configuration with outer cassette cover 320 removed. Cassette 300includes a y-connector support assembly 322, an axial drive assembly324, and a rotational drive assembly 326. Generally, the variousportions of cassette 300 are placed in the loading configuration toallow the user to load or install a guide wire and/or working catheterinto cassette 300. Further, in the exemplary embodiment shown,y-connector support assembly 322 is located in front of axial driveassembly 324, and axial drive assembly 324 is located in front ofrotational drive assembly 326 within cassette 300.

Y-connector support assembly 322 includes a chassis 328 and ay-connector restraint 330. Base plate 318 includes a support arm 332that supports y-connector support assembly 322. Chassis 328 is coupledto the front of support arm 332 via pin connection 334.

A central groove or depression 336 extends the length of chassis 328.Y-connector 338 rests within central groove 336 of chassis 328.Y-connector 338 includes a first leg 340, a second leg 342, and a thirdleg 344. First leg 340 is configured to attach to a guide catheter suchthat the central lumen of the y-connector is in fluid communication withthe central lumen of the guide catheter. Second leg 342 is angled awayfrom the longitudinal axis of y-connector 338. Second leg 342 ofy-connector 338 allows introduction of a contrast agent or medicine intothe lumen of the guide catheter. A one way valve prohibits bodily fluidfrom exiting second leg 342. Third leg 344 extends away from the guidecatheter toward axial drive assembly 324. In use, guide wire 301 andworking catheter 303 are inserted into third leg 344 of y-connector 338via opening 346 and may be advanced through y-connector 338 into thelumen of the guide catheter. The third leg also includes a one way valvethat permits insertion and removal of the working catheter and guidewire but prohibits bodily fluids from exiting third leg 344.

Chassis 328 is rotatable about an axis defined by pin connection 334 toallow chassis 328 to be placed in the “loading position” shown in FIG.17. In the loading position, chassis 328 is positioned at about a 45degree angle, shown by angle line 315, relative to support arm 332.Chassis 328 is moved to the “loading position” to provide easier accessto opening 346 of the third leg 344 allowing the user to feed guide wire301 and working catheter 303 into y-connector 338.

Y-connector support assembly 322 includes y-connector restraint 330.Y-connector restraint 330 is configured to releasably engage y-connector338. In the engaged position shown in FIG. 17, engagement arm 348 ofy-connector restraint 330 engages or presses y-connector 338 intocentral groove 336 to securely hold y-connector 338. Y-connectorrestraint 330 may be moved to a disengaged position to releasey-connector 338 from chassis 328.

Cassette 300 also includes an axial drive assembly 324. Axial driveassembly 324 includes a first axial drive mechanism, shown as guide wireaxial drive mechanism 350, and a second axial drive mechanism, shown asworking catheter axial drive mechanism 352. Axial drive assembly 324also includes a top deck 354, a cover 356, and a latch or handle 358.

Generally, guide wire axial drive mechanism 350 is configured toreleasably engage and drive (e.g., to impart motion to) guide wire 301along its longitudinal axis. In this manner, guide wire axial drivemechanism 350 provides for advancement and/or retraction of guide wire301. Working catheter axial drive mechanism 352 is configured toreleasably engage and drive (e.g., to impart motion to) working catheter303 along its longitudinal axis. In this manner, working catheter axialdrive mechanism 352 provides for advancement and/or retraction ofworking catheter 303.

Top deck 354 is mounted to a central portion 360 of base plate 318. Topdeck 354 includes a guide wire channel 364 and a working catheterchannel 366. Guide wire channel 364 is positioned generallyperpendicular to the top surface of top deck 354 and runs the length oftop deck 354 in the longitudinal direction. Working catheter channel 366is positioned generally perpendicular to the top surface of top deck 354and is located at an angle relative to guide wire channel 364. Aplurality of tabs 368 extend vertically from the top surface of top deck354 along guide wire channel 364.

In FIG. 17, cover 356 is shown in the open position. Handle 358 is movedto a position generally parallel to the longitudinal axis of cassette300 to allow cover 356 to move to the open position. Cover 356 ismounted to top deck 354 via hinges 370. Cassette 300 includes arestraint structure that acts to restrain movement of the guide wirewhen cover 356 is in the closed position. As shown, the restraintstructure includes a plurality of tabs 372 extending from the lowersurface of cover 356. Tabs 372 are positioned such that when cover 356is closed, tabs 372 are positioned within a portion of guide wirechannel 364 between tabs 368 such that tabs 372 restrain movement ofguide wire 301 in a vertical direction (i.e., restrains movement of theguide wire in a direction perpendicular to the top surface of top deck354).

When cover 356 is in the open position, both guide wire axial drivemechanism 350 and working catheter axial drive mechanism 352 are exposedallowing the user to load cassette 300 with a guide wire and workingcatheter. With cover 356 open, guide wire 301 is loaded into axial driveassembly 324 by placing the guide wire into guide wire channel 364. Tabs368 facilitate the placement of guide wire 301 by aiding the user inaligning the guide wire with guide wire channel 364. In addition,working catheter 303 is loaded into axial drive assembly 324 by placingthe working catheter into working catheter channel 366. As will bedescribed in more detail below, once the guide wire and working catheterare positioned within guide wire channel 364 and working catheterchannel 366, respectively, engagement surfaces of guide wire axial drivemechanism 350 and working catheter axial drive mechanism 352 are broughtinto engagement with the guide wire and working catheter respectively.

Both top deck 354 and central portion 360 of base plate 318 are shapedto define a recess 374. Working catheter channel 366 includes an opening376 located within recess 374. Recess 374 allows opening 376 to becloser to y-connector 338 and also closer to the entry incision allowingworking catheter 303 to be advanced farther into the patient's vascularsystem than if opening 376 were located further away from y-connector338 or the entry incision. As can be seen in FIG. 16, working catheter303 includes a hub 305 at its proximal end that is too large to fitthrough opening 376. Thus, the closer that opening 376 is to y-connector338 and to the entry incision the further working catheter 303 can beadvanced into the patient's vascular system.

Cassette 300 also includes a rotational drive assembly 326. Rotationaldrive assembly 326 includes a rotational drive mechanism, shown as guidewire rotational drive mechanism 380, a cover 384, and a journal 388.Guide wire rotational drive mechanism 380 includes a chassis 382 and anengagement structure 386. Rotational drive assembly 326 is configured tocause guide wire 301 to rotate about its longitudinal axis. Engagementstructure 386 is configured to releasably engage guide wire 301 and toapply sufficient force to guide wire 301 such that guide wire 301 isallowed to rotate about its longitudinal axis while permitting guidewire 301 to be moved axially by guide wire axial drive mechanism 350.

In the embodiment shown, rotational drive assembly 326 is supportedwithin housing 316 such that rotation drive assembly 326 is permitted torotate within housing 316. Engagement structure 386 applies sufficientforce to guide wire 301 that the rotation of rotation drive assembly 326causes guide wire 301 to rotate about its longitudinal axis asrotational drive assembly 326 rotates.

Chassis 382 includes a guide wire channel 390. Guide wire channel 390 ispositioned generally perpendicular to the top surface of chassis 382 andruns the length of chassis 382 in the longitudinal direction. Aplurality of tabs 392 extend vertically from the top surface of chassis382 along guide wire channel 390. In FIG. 17, cover 384 is shown in theopen position. Cover 384 is mounted to chassis 382 via hinge 394.Cassette 300 includes a restraint structure that acts to restrainmovement of the guide wire when cover 384 is in the closed position. Asshown, the restraint structure includes a plurality of tabs 396extending from the lower surface of cover 384. The top surface ofchassis 382 includes a plurality of recesses 398 configured to receivetabs 396 when cover 384 is in the closed position. Tabs 396 arepositioned such that when cover 384 is closed, tabs 396 are positionedover guide wire channel 390 such that tabs 396 prevent guide wire 301from falling out of guide wire channel 390 (i.e., restrains movement ofthe guide wire in a direction perpendicular to the top surface ofchassis 382). In addition, the sidewalls of guide wire channel 390 andthe engagement surfaces of wheels 522 and 524 prevent or restrainmovement of guide wire 301 in other directions perpendicular to thelongitudinal axis of guide wire 301. Thus, tabs 392 and guide wirechannel 390 hold guide wire 301 within channel 390 during rotation ofrotational drive assembly 326.

When cover 384 is in the open position, guide wire channel 390 isexposed allowing the user to load cassette 300 with a guide wire. Withcover 384 open, guide wire 301 is loaded into rotational drive assembly326 by placing the guide wire into guide wire channel 390. Tabs 392facilitate the placement of guide wire 301 by aiding the user inaligning the guide wire with guide wire channel 390. As will bedescribed in more detail below, once guide wire 301 is positioned withinguide wire channel 390 engagement surfaces of engagement structure 386are brought into engagement with the guide wire. In one embodiment, whenthe user activates controls (e.g., controls located at workstation 14)to open cover 384, rotational drive assembly 326 is automaticallyrotated such that guide wire channel 390 is facing generally upward toallow for easy loading or removal of guide wire 301.

In one embodiment, cassette 300 is a modular cassette that allowsvarious components of cassette 300 to be removed and/or switched outwith other components. In an exemplary embodiment, a user may wish tocontrol the guide wire using bedside system 12 and to control theworking catheter manually. In this embodiment, a user may mount onlyguide wire axial drive mechanism 350 and rotational drive assembly 326within housing 316 of cassette 300. In another exemplary embodiment, auser may wish to control the working catheter using bedside system 12and to control the guide wire manually. In this embodiment, a user maymount only working catheter drive mechanism 352 within housing 316 ofcassette 300. In another embodiment, cassette 300 may include additionallocations for mounting drive mechanisms for any type of additionalcatheter devices that may be used during a procedure. For example, auser may be able to couple drive mechanisms to cassette 300 to controlthe movement and/or control of an intravascular ultrasound catheter.

Referring to FIG. 18, cassette 300 is shown in the “loaded” or “use”position. In the “loaded” position, y-connector support assembly 322 isrotated downward such that y-connector 338 is aligned with guide wirechannel 364 of axial drive assembly 324. The axial alignment allowsguide wire 301 and working catheter 303 to be moved into and/or out ofy-connector 338 via operation of guide wire axial drive mechanism 350and working catheter axial drive mechanism 352. Cover 356 is shown inthe closed position overlying both the guide wire axial drive mechanism350 and the working catheter axial drive mechanism 352. As shown, cover356 also covers guide wire channel 364 and working catheter channel 366.As such, cover 356 acts to prevent interference with the variouscomponents of axial drive assembly 324 during use.

After cover 356 is moved to the closed position, handle 358 is rotatedapproximately 90 degrees such that a portion of handle 358 is positionedover cover 356. As will be discussed in greater detail below, rotationof handle 358 to the closed position shown in FIG. 18 causes theengagement surface of the guide wire axial drive mechanism 350 and ofthe working catheter axial drive mechanism 352 to move together engagingthe guide wire and working catheter, respectively.

In addition, when cassette 300 is moved to the “loaded” position, cover384 is moved to the closed position overlying rotational drive mechanism380 and guide wire channel 390 as shown in FIG. 18. Like cover 356,cover 384 acts to prevent interference with the various components ofrotational drive assembly 326 during use. In one embodiment, a user mayactivate controls (e.g., controls located at workstation 14) to causethe various components of cassette 300 to move between the “loading” and“loaded” positions. In addition, cassette 300 may also be configured toallow the user to move the various components of cassette 300 betweenthe “loading” and “loaded” positions manually.

Referring to FIG. 18, in the “loaded” or “use” configuration, thelongitudinal axis (and the internal lumen) of y-connector 338 is alignedwith guide wire channel 364 of axial drive assembly and with guide wirechannel 390 of rotational drive assembly 326. This alignment provides apath extending from the rear of cassette 300 through y-connector 338into the guide catheter through which the guide wire is advanced orretracted during axial movement of the guide wire. In variousembodiments, components of cassette 300, including top deck 354, chassis382, cover 356, and cover 384, may be made from a transparent ortranslucent plastic.

Referring to FIG. 19, an exploded perspective view from above of axialdrive assembly 324 is shown. FIG. 19 generally depicts the components ofaxial drive assembly 324. Guide wire axial drive mechanism 350 andworking catheter axial drive mechanism 352 are positioned above baseplate 318 and top deck 354 is fastened to central portion 360 of baseplate 318 above guide wire axial drive mechanism 350 and workingcatheter axial drive mechanism 352. Thus, guide wire axial drivemechanism 350 and working catheter axial drive mechanism 352 aregenerally enclosed within a chamber defined by top deck 354 and centralportion 360 of base plate 318 when axial drive assembly 324 isassembled. Top deck 354 includes a plurality of apertures 362 to receivevarious portions of both axial drive mechanism 350 and working catheteraxial drive mechanism 352.

Axial drive mechanism 350 includes a drive element 400, a first rollerassembly 402, a second roller assembly 404, and a guide wire axialmotion sensor assembly, shown as encoder assembly 406. First rollerassembly 402 and second roller assembly 404 are both mounted within ahousing 416. Drive element 400 includes a drive shaft 408, a drive wheel410, a bearing 412, and a screw 414. Drive shaft 408 is configured toengage second capstan 306 of motor drive base 302 such that drive shaft408 and drive wheel 410 rotate in response to rotation of second capstan306. First roller assembly 402 includes an idler wheel or roller 418, awheel housing 420, a bearing 422, and a spring 424.

Drive wheel 410 includes an outer or engagement surface 426, and roller418 includes an outer or engagement surface 428. Generally, when guidewire axial drive mechanism 350 is placed in the “use” or “engaged”position (shown in FIG. 22), guide wire 301 is positioned between drivewheel 410 and roller 418 such that engagement surface 426 of drive wheel410 and engagement surface 428 of roller 418 are able to engage theguide wire. In this embodiment, engagement surface 426 and engagementsurface 428 define a pair of engagement surfaces. The force applied toguide wire 301 by engagement surface 426 and engagement surface 428 issuch that drive wheel 410 is able to impart axial motion to guide wire301 in response to the rotation of drive shaft 408 caused by rotation ofsecond capstan 306. This axial motion allows a user to advance and/orretract a guide wire via manipulation of controls located at workstation14. Roller 418 is rotatably mounted within wheel housing 420 and rotatesfreely as drive wheel 410 rotates to drive guide wire 301. Spring 424 isbiased to exert a force onto wheel housing 420 causing roller 418 toengage the guide wire against drive wheel 410. Spring 424 is selected,tuned, and/or adjusted such that the proper amount of force is appliedto guide wire 301 by engagement surface 426 and engagement surface 428in the “engaged” position. In other embodiments, additional driveelements may be added as necessary to impart axial motion to the guidewire.

Second roller assembly 404 includes an idler wheel or roller 430, awheel housing 432, a bearing 434, and a spring 436. Encoder assembly 406includes shaft 438, magnetic coupling 440, idler wheel or roller 442,bearing 444, and a screw 446. Roller 430 includes an outer or engagementsurface 448 and roller 442 includes an outer or engagement surface 450.

In the “engaged” position, guide wire 301 is positioned between roller430 and roller 442 such that engagement surface 448 of roller 430 andengagement surface 450 of roller 442 are able to engage the guide wire.In this embodiment, engagement surface 448 and engagement surface 450define a pair of engagement surfaces. The force applied to guide wire301 by engagement surface 448 and engagement surface 450 is such thatdrive wheel 410 is able to pull guide wire 301 past roller 430 and 442.In this way, the pair of non-active or idle rollers 430 and 442 helpsupport guide wire 301 and maintain alignment of guide wire 301 alongthe longitudinal axis of cassette 300.

Roller 430 is rotatably mounted within wheel housing 432, and roller 442is rotatably mounted to shaft 438. Both rollers 430 and 442 are mountedto rotate freely as drive wheel 410 imparts axial motion to guide wire301. Spring 436 is biased to exert a force onto wheel housing 432causing roller 430 to engage guide wire 301 against roller 442. Spring436 is selected, tuned, and/or adjusted such that the proper amount offorce is applied to guide wire 301 by engagement surface 448 andengagement surface 450 in the “engaged” position to support the guidewire while still allowing the guide wire to be moved axially by drivewheel 410. In other embodiments, additional pairs of non-active or idlerrollers may be added as needed to provide proper support and alignmentfor the guide wire. In one embodiment, spring 424 and spring 436 areselected or adjusted such that the force applied to guide wire 301 bywheels 430 and 442 is approximately the same as the force applied toguide wire 301 by wheels 410 and 418.

Encoder assembly 406 includes magnetic coupling 440 that engages amagnetic encoder located within motor drive base 302. The magneticencoder is configured to measure an aspect (e.g., speed, position,acceleration, etc.) of axial movement of the guide wire. As roller 442rotates, shaft 438 rotates causing magnetic coupling 440 to rotate. Therotation of magnetic coupling 440 causes rotation of the magneticencoder within motor drive base 302. Because rotation of roller 442 isrelated to the axial movement of guide wire 301, the magnetic encoderwithin motor drive base 302 is able to provide a measurement of theamount of axial movement experienced by guide wire 301 during aprocedure. This information may be used for a variety of purposes. Forexample, this information may be displayed to a user at workstation 14,may be used in a calculation of or estimated position of the guide wirewithin the vascular system of a patient, may trigger an alert or alarmindicating a problem with guide wire advancement, etc.

As shown in FIG. 19, first roller assembly 402 and second rollerassembly 404 are both mounted within a housing 416. Housing 416 providesa common support for first roller assembly 402 and second rollerassembly 404. As will be discussed in more detail below, first rollerassembly 402 and second roller assembly 404 are moved away from drivewheel 410 and roller 442, respectively, when axial drive assembly 324 isplaced in the “loading” configuration. This facilitates placement ofguide wire 301 between the opposing pairs of engagement surfaces ofguide wire axial drive mechanism 350. Housing 416 allows first rollerassembly 402 and second roller assembly 404 to be moved together (e.g.,in sync) away from drive wheel 410 and roller 442, respectively, whenaxial drive assembly 324 is placed in the “load” configuration.

Axial drive assembly 324 also includes working catheter axial drivemechanism 352. Working catheter axial drive mechanism 352 includes adrive element 452 and a working catheter axial motion sensor assembly,shown as working catheter encoder assembly 454. Drive element 452includes a drive shaft 456, a drive wheel 458, a bearing 460, and ascrew 462. Drive shaft 456 is configured to engage first capstan 304 ofmotor drive base 302 such that drive shaft 456 and drive wheel 458rotate in response to rotation of first capstan 304. Encoder assembly454 includes shaft 464, a roller 466, an encoder linkage 468, a spring470, and a magnetic coupling 480.

Drive wheel 458 includes an outer or engagement surface 472 and roller466 includes an outer or engagement surface 474. When working catheteraxial drive mechanism 352 is in the “engaged” position, a workingcatheter is positioned between drive wheel 458 and roller 466, such thatengagement surface 472 and engagement surface 474 are able to engageworking catheter 303. In this embodiment, engagement surfaces 472 and474 define a pair of engagement surfaces. The force applied to workingcatheter 303 by engagement surfaces 472 and 474 is such that drive wheel458 is able to impart axial motion to the working catheter in responseto the rotation of drive shaft 456 caused by rotation of first capstan304. This axial motion allows a user to advance and/or retract a workingcatheter via manipulation of controls located at workstation 14. Roller466 is rotatably mounted to shaft 464 and rotates freely as drive wheel458 rotates to drive the working catheter.

Spring 470 is coupled to a first end of linkage 468. The second end oflinkage 468 includes an aperture 476 that is pivotally coupled to a post478 extending from the inner surface of top deck 354. Spring 470 isbiased to exert a force on to linkage 468 causing linkage 468 to pivotabout post 478 to force roller 466 to engage working catheter 303against drive wheel 458. Spring 470 is selected, tuned, and/or adjustedsuch that the proper amount of force is applied to working catheter 303by engagement surfaces 472 and 474 in the “engaged” position to allowdrive wheel 458 to impart axial movement to the working catheter.

Encoder assembly 454 includes magnetic coupling 480 that engages amagnetic encoder located within motor drive base 302. The magneticencoder is configured to measure an aspect (e.g., speed, position,acceleration, etc.) of axial movement of the working catheter. As roller466 rotates, shaft 464 rotates causing magnetic coupling 480 to rotate.The rotation of magnetic coupling 480 causes rotation of the magneticencoder within motor drive base 302. Because rotation of roller 466 isrelated to the axial movement of working catheter 303, the magneticencoder within motor drive base 302 is able to provide a measurement ofthe amount of axial movement experienced by the working catheter duringa procedure. This information may be used for a variety of purposes. Forexample, this information may be displayed to a user at workstation 14,may be used in a calculation of or estimated position of the workingcatheter within the vascular system of a patient, may trigger an alertor alarm indicating a problem with working catheter advancement, etc.

As will be discussed in more detail below, roller 466 is moved away fromdrive wheel 458 when axial drive assembly 324 is placed in the “loading”configuration. This facilitates placement of the working catheterbetween the opposing pairs of engagement surfaces of working catheteraxial drive mechanism 352.

In one embodiment, cassette 300 and/or motor drive base 302 includes alocking mechanism that is configured to lock the position of guide wire301 during manipulation of the working catheter 303 and to lock theposition of working catheter 303 during manipulation of guide wire 301.In one embodiment, the locking mechanism acts to increase the forceapplied to the guide wire by the engagement surfaces when the workingcatheter is being advanced and to increase the force applied to theworking catheter by the engagement surfaces when the guide wire is beingadvanced.

Referring to FIGS. 19 and 20, top deck 354 includes a plurality ofcylindrical sleeves, first sleeve 482, second sleeve 484, and thirdsleeve 486, extending from the inner or lower surface of top deck 354.Top deck 354 also includes a plurality of cylindrical collars, firstcollar 488, second collar 490, and third collar 492, extending from theupper surface of top deck 354. Collar 488 is in axial alignment withsleeve 482. Collar 490 is in axial alignment with sleeve 484. Collar 492is in axial alignment with sleeve 486. Each of the collars 488, 490, and492 define an aperture 362. In the embodiment shown, sleeve 482 andcollar 488 are configured to receive working catheter drive element 452,sleeve 484 and collar 490 are configured to receive guide wire driveelement 400, and sleeve 486 and collar 492 are configured to receiveguide wire encoder assembly 406. Apertures 362 provide access to screws414, 446, and 462 once top deck 354 is mounted over axial drive assembly324.

Top deck 354 includes a collar 494 aligned with and located at the backend of guide wire channel 364. Collar 494 is configured to receive frontshaft 512 that extends from chassis 382 of rotational drive assembly326. Collar 494 is configured to allow front shaft 512 (and consequentlythe rest of rotational drive assembly 326) to rotate about thelongitudinal axis of guide wire channel 390 relative to axial driveassembly 324. In one embodiment, rotational drive assembly 326 is ableto rotate relative to housing 316 of cassette 300 while axial driveassembly 324 does not rotate relative to housing 316. In anotherembodiment, both rotational drive assembly 326 and axial drive assembly324 rotate relative to housing 316 of cassette 300.

FIG. 20 is a bottom perspective view of cassette 300 showing top deck354 mounted above guide wire axial drive mechanism 350 and workingcatheter axial drive mechanism 352. FIG. 20 shows working catheter driveelement 452, guide wire drive element 400, and guide wire encoderassembly 406 received within sleeves 482, 484, and 486. A supportstructure 496 extends from the lower surface of top deck 354. Spring 470is coupled at one end to support structure 496 allowing spring 470 tocompress and expanded between linkage 468 and support structure 496.

As shown, the lower end of drive shaft 408 includes a keyed recess 498,and the lower end of drive shaft 456 includes a keyed recess 500. Keyedrecess 500 is one embodiment of first capstan socket 310, and keyedrecess 498 is one embodiment of second capstan socket 312. Keyed recess500 is configured to receive a capstan, such as first capstan 304, andkeyed recess 498 is configured to receive a capstan, such as secondcapstan 306. First capstan 304 and second capstan 306 are keyed to fitwithin keyed recess 500 and 498 and to engage and turn drive shafts 456and 408 upon rotation of the capstans.

As shown, magnetic coupling 440 of guide wire encoder assembly 406includes a circular array of magnets 504. Magnetic coupling 480 ofworking catheter encoder assembly 454 includes a circular array ofmagnets 506. Magnetic couplings 440 and 480 engage with magneticencoders positioned within motor drive base 302. The magnetic encodersof motor drive base 302 are coupled to appropriate electronics to detectand measure rotation of rollers 442 and 466 and to calculate axialmotion of guide wire 301 and working catheter 303 based on the measuredrotations. While this embodiment discloses the use of magnetic encodersto detect the axial motion of the guide wire and working catheter, othersensors may be used. In one embodiment, axial motion of the guide wiremay be detected by an optical sensor that detects movement of the guidewire and/or working catheter by scanning the surface of the guide wireand/or working catheter as it passes the optical sensor. In one suchembodiment, the optical sensor includes an LED light source and adetector (e.g., a complimentary metal oxide semiconductor, other lightdetecting circuitry, etc.) that detects light reflected off the surfaceof the guide wire and/or working catheter, and the light detected by thedetector is analyzed (e.g., by a digital signal processor) to determinemovement of the guide wire and/or working catheter. In anotherembodiment, the surface of the guide wire and/or working catheter mayinclude indicia that are detected to determine axial movement of theguide wire. In other embodiments, other types of sensors (e.g.,resolvers, sychros, potentiometers, etc.), may be used to detectmovement of the guide wire and/or working catheter.

Cassette 300 also includes a series of magnets 508 positioned belowguide wire channel 364. Because, in at least some embodiments, the guidewire is made from a magnetic material, magnets 508 are able to interactwith the guide wire. In this embodiment, the magnetic attraction createdby magnets 508 helps the user position guide wire 301 during loading bydrawing guide wire 301 into guide wire channel 364. The magneticattraction created by magnets 508 also tends to hold guide wire 301within guide wire channel 364 during advancement and/or retraction ofthe guide wire. Further, magnets 508 help to hold guide wire 301straight (i.e., parallel to the longitudinal axis of guide wire channel364) to aid in the axial movement caused by guide wire axial drivemechanism 350.

FIG. 21 shows a top view of axial drive assembly 324 in the “loading”configuration with handle 358 (shown in broken lines) rotated such thatit is generally parallel to guide wire channel 364. FIG. 22 shows a topview of axial drive assembly 324 in the “loaded” or “use” configurationwith handle 358 rotated such that it is generally perpendicular to guidewire channel 364. Generally, when handle 358 is moved from the positionof FIG. 22 to the position of FIG. 21, the engagement surfaces of bothguide wire axial drive mechanism 350 and working catheter axial drivemechanism 352 are moved away from each other increasing the spacebetween the pairs of wheels in the drive mechanisms. This providessufficient space between the wheels of each drive mechanism to allow theuser to place guide wire 301 and working catheter 303 into the channelsbetween the wheels. Generally, as handle 358 is moved from the positionof FIG. 21 to the position of FIG. 22, the engagement surfaces of bothguide wire axial drive mechanism 350 and working catheter axial drivemechanism 352 are moved toward each other bringing the engagementsurfaces of each drive mechanism into engagement with guide wire 301 orworking catheter, respectively.

In the embodiment shown, handle 358 is coupled to a shaft 357. Shaft 357includes a cam section 359 and housing 416 includes a cam surface 417.As handle 358 rotates from the position shown in FIG. 21 to the positionshown in FIG. 22, cam section 359 of shaft 357 moves along cam surface417 causing housing 416 to move toward guide wire 301. This motionengages guide wire 301 between drive wheel 410 and roller 418 andbetween roller 430 and roller 442. When handle 358 is brought into theposition of FIG. 22, springs 424 and 436 are compressed to the propertension to allow drive wheel 410 to move guide wire 301 axial along itslongitudinal axis.

In addition, housing 416 includes a tab 419 that is coupled to linkage468. Thus, linkage 468 rotates about post 478 when housing 416 is movedto the position shown in FIG. 21. This movement draws roller 466 awayfrom working catheter drive wheel 458. When, housing 416 is moved to theposition shown in FIG. 22, roller 466 is moved toward catheter drivewheel 458 such that the engagement surfaces of roller 466 and drivewheel 458 engage working catheter 303. In one embodiment, cassette 300is configured to allow the user to move the axial drive assembly 324between the “use” and “loading” positions via manipulation of controlsat workstation 14. Cassette 300 may also be configured to allow the userto move the axial drive assembly 324 between the “use” and “loading”position manually.

FIGS. 23A and 23B show a perspective view of rotational drive assembly326 showing cover 384 in the open position. Rotational drive assembly326 includes rotational drive mechanism 380, chassis 382, an engagementstructure 386, and a disengagement assembly 510. Chassis 382 fits overengagement structure 386 and provides mounting for various components ofrotational drive assembly 326. Chassis 382 includes a front shaft 512and a rear shaft 514. As discussed above, front shaft 512 is rotatablyreceived within collar 494 of top deck 354, and rear shaft 514 isrotatably received within collar 516 such that rotational drivemechanism 380 is able to rotate relative to journal 388. As shown,collar 516 extends through and is supported by journal 388 such thatrear shaft 514 rotates within collar 516 as rotational drive mechanism380 is rotated. Collar 516 rests within a recess or slot formed withinjournal 388. In another embodiment, rear shaft 514 may be in directcontact with journal 388 such that rear shaft 514 rotates within therecess or slot of journal 388 as rotational drive mechanism 380 isrotated. Guide wire channel 390 extends the length of chassis 382through both front shaft 512 and rear shaft 514.

Rotational drive mechanism 380 includes rotation bevel gear 518 thatengages a drive gear 520. Bevel gear 518 is rigidly coupled to frontshaft 512 of chassis 382 such that rotation of bevel gear 518 rotateschassis 382. Drive gear 520 is coupled to a rotational actuatorpositioned in motor drive base 302 and engages bevel gear 518. Rotationof the rotational actuator in motor drive base 302 causes drive gear 520to rotate which causes bevel gear 518 to rotate which in turn causesrotational drive mechanism 380 to rotate. Rotational drive mechanism 380is allowed to rotate about the longitudinal axis of guide wire channel390 via the rotatable connections between front shaft 512 and top deck354 and between rear shaft 514 and journal 388. Bevel gear 518 furtherincludes a slot 519 in axial alignment with guide wire channel 390. Slot519 allows the user to place guide wire 301 into guide wire channel 390by dropping it in vertically as opposed to threading it through bevelgear 518. In one embodiment, rotational drive assembly 326 is equippedwith one or more sensors that are configured to measure an aspect (e.g.,speed, position, acceleration, etc.) of rotation of the guide wireand/or any other structure of rotational drive assembly 326. The sensorsthat measure rotation of the guide wire may include magnetic encodersand/or optical sensors as discussed above regarding the sensors thatmeasure axial motion of the guide wire and/or working catheter. However,any suitable sensor (e.g., resolvers, sychros, potentiometers, etc.) maybe used to detect rotation of the guide wire.

Referring to FIG. 23B, engagement structure 386 is shown according to anexemplary embodiment. As shown, engagement structure 386 includes fourpairs of idler wheels or rollers. Each pair of rollers includes a fixedwheel 522 and an engagement wheel 524. Fixed wheels 522 are rotatablycoupled to chassis 382 via fixation posts 530. Each engagement wheel 524is part of an engagement wheel assembly 523. Each engagement wheelassembly 523 includes a pivot yoke 532 and a spring 536. Each engagementwheel is mounted to pivot yoke 532 via a mounting post 538. Each pivotyoke 532 is pivotally coupled to chassis 382 via fixation posts 534.

Each fixed wheel 522 includes an outer or engagement surface 526 andeach engagement wheel 524 includes an outer or engagement surface 528.Generally, FIG. 23B shows engagement structure 386 in the “use” or“engaged” position. In the “engaged” position, guide wire 301 ispositioned between fixed wheels 522 and engagement wheels 524 such thatengagement surfaces 526 and 528 are able to engage guide wire 301. Inthis embodiment, engagement surface 526 and engagement surface 528 ofeach pair of rollers define a pair of engagement surfaces. The forceapplied to guide wire 301 by engagement surfaces 526 and 528 issufficient to cause the guide wire to rotate about its longitudinal axisas rotational drive assembly 326 is rotated. Further, the force appliedto guide wire 301 by engagement surfaces 526 and 528 is also sufficientto allow the guide wire to be moved axially by guide wire axial drivemechanism 350.

Springs 536 are biased to exert a force onto pivot yokes 532 causingeach engagement wheel 524 to engage the opposite fixed wheel 522. Thegenerally L-shape of pivot yoke 532 allows springs 536 to be alignedwith the longitudinal axis of guide wire 301 and still cause engagementbetween engagement wheels 524, fixed wheels 522, and the guide wire.This allows the lateral dimension of rotational drive assembly 326 to beless than if springs 536 were positioned perpendicular to thelongitudinal axis of the guide wire. Springs 536 are selected, tuned,and/or adjusted such that the proper amount of force is applied to theguide wire by engagement surfaces 526 and 528 in the “engaged” position.

Cassette 300 also includes a series of magnets 540 located beneath guidewire channel 390. Because, in at least some embodiments the guide wireis made from a magnetic material, magnets 540 are able to interact withthe guide wire. In this embodiment, the magnetic attraction created bymagnets 540 helps the user position guide wire 301 during loading bydrawing guide wire 301 into guide wire channel 390. The magneticattraction created by magnets 540 also tends to hold guide wire 301within guide wire channel 390 during advancement and/or retraction ofthe guide wire. Further, magnets 540 help to hold guide wire 301straight (i.e., parallel to the longitudinal axis of guide wire channel390) to aid in the axial movement caused by guide wire axial drivemechanism 350.

Rotational drive assembly also includes a disengagement assembly 510.Disengagement assembly 510 includes a stepped collar 542, a base plate544, and a spring 546. Stepped collar 542 is coupled to base plate 544,and spring 546 is coupled at one end to chassis 382 and at the other endto base plate 544. Stepped collar 542 includes a slot 548 in axialalignment with guide wire channel 390. Like slot 519, slot 548 allowsthe user to place guide wire 301 into guide wire channel 390 by droppingit in vertically as opposed to threading it through stepped collar 542.Base plate 544 includes a plurality of engagement arms 550 that extendgenerally perpendicular to the plane defined by base plate 544.

Generally, disengagement assembly 510 allows engagement wheels 524 to bemoved away from fixed wheels 522. Referring to FIGS. 24 and 25, FIG. 25shows a top view of rotational drive assembly 326 in the “loading”configuration, and FIG. 24 shows a top view of rotational drive assembly326 in the “loaded” or “use” configuration. To cause engagement wheels524 to disengage from guide wire 301, an axially directed force(depicted by the arrow in FIG. 25) is applied to stepped collar 542.This causes base plate 544 to move toward the front of cassette 300 inthe direction of the arrow. As base plate 544 moves forward, spring 546is compressed, and engagement arms 550 are brought into contact withpivot yokes 532. The contact between engagement arms 550 and pivot yokes532 causes springs 536 to be compressed, and pivot yokes 532 pivot aboutfixation posts 534. As pivot yokes 532 pivot, engagement wheels 524 aredrawn away from fixed wheels 522. As shown in FIG. 25, this providessufficient space between engagement wheels 524 and fixed wheels 522 toallow the user to place guide wire 301 into guide wire channel 390.

When the axial force is removed from stepped collar 542, engagementwheels 524 move from the position shown in FIG. 25 to the “engaged”position shown in FIG. 24. When the axial force is removed, spring 546and springs 536 are allowed to expand causing engagement arms 550 todisengage from pivot yokes 532. Pivot yokes 532 pivot counter-clockwiseabout fixation posts 534, bringing engagement wheels 524 back towardguide wire channel 390 causing engagement surfaces 526 of fixed wheels522 and engagement surfaces 528 of engagement wheels 524 to engage guidewire 301.

In one embodiment, a user may activate controls located at workstation14 to cause rotational drive assembly 326 to move between the “use”position and the “loading” position. In this embodiment, rotationaldrive assembly 326 is automatically rotated such that guide wire channel390 is facing generally upward to allow for easy loading or removal ofthe guide wire. In the embodiment shown, chassis 382 rotates relative tostepped collar 542. In this embodiment, when rotational drive assembly326 is in the “loading” position, a path defined by the engagementsurfaces of engagement structure 386 and guide wire channel 390 alignwith slot 548 of stepped collar 542. Motor drive base 302 may alsoinclude a structure (e.g., two rods, etc.) that applies the axial forceto stepped collar 542 in response to a user's activation of controlslocated at workstation 14. The structure applies the axial force to thestepped collar 542 to cause engagement structure 386 to disengage fromthe guide wire. Next, cover 384 is moved from the closed position to theopen position allowing the user to access guide wire channel 390 toeither remove or install the guide wire. In one embodiment, cassette 300and/or motor drive base 302 includes motors or other actuators thatcause the covers of cassette 300 to open in response to a user'sactivation of controls at workstation 14.

FIG. 26 shows a cross-sectional view of rotational drive assembly 326 asindicated by the corresponding sectional line in FIG. 18. FIG. 26depicts guide wire 301 within guide wire channel 390. As shown, in FIG.26 when cover 384 is in the closed position, tab 396 rests over guidewire channel 390. As shown in FIG. 26, tab 396 helps hold guide wire 301in guide wire channel 390 by restricting movement of guide wire 301 in adirection perpendicular to the plane defined by base plate 544 (thisdirection of restriction is the vertical direction in the orientation ofFIG. 26). Guide wire 301 is engaged on one side by engagement surface526 of fixed wheel 522 and on the other side by engagement surface 528of engagement wheel 524.

FIG. 27 shows a cross-sectional view of axial drive assembly 324 asindicated by the corresponding sectional line in FIG. 18. FIG. 27depicts guide wire 301 within channel 364. Guide wire 301 is engaged onone side by engagement surface 426 of drive wheel 410 and on the otherside by engagement surface 428 of roller 418.

Under certain circumstances, it may be desirable to disconnectrotational drive assembly 326 from cassette 300. Referring to FIGS.28A-28C, cassette 300 may be configured to allow rotational driveassembly 326 (shown schematically by broken lines in FIGS. 28A-28C) tobe disconnected from cassette 300. In one such embodiment, cassette 300includes journal 388, and rotational drive mechanism 380 is rotatablycoupled to journal 388. In this embodiment, journal 388 is releasablycoupled to housing 316 such that both journal 388 and rotational drivemechanism 380 may be removed from housing 316 without removing the guidewire from the patient and/or without removing cassette 300 from base302. In one such embodiment, following release of journal 388 fromhousing 316, the user may remove (e.g., pull, slide, etc.) both journal388 and rotational drive mechanism 380 over the proximal end of theguide wire.

In one embodiment, journal 388 includes a slot 552, and base plate 318includes a release button 554. Release button 554 is coupled to ramp556, and ramp 556 includes wedge-shaped end 558. As shown in FIG. 28A,wedge-shaped end 558 passes through slot 552 to couple journal 388 tobase plate 318. When a downward force is applied to release button 554,wedge-shaped end 558 is allowed to disengage from slot 552 allowingrotational drive assembly 326 and journal 388 to disconnect from baseplate 318.

Next, rotational drive assembly 326 is disengaged from guide wire 301.As discussed above, regarding FIGS. 24 and 25, by applying an axialforce to stepped collar 542, engagement structure 386 disengages fromthe guide wire. Once engagement structure 386 is disengaged from guidewire 301, the rotational drive assembly 326 may be moved over theproximal end of the guide wire while the guide wire slides freely thoughguide wire channel 390. Removal of rotational drive assembly 326 fromcassette 300 may be necessary if, for example, bedside system 12 losespower preventing motor drive base 302 from placing rotational driveassembly into the “loading” configuration. In this case, removal ofrotational drive assembly 326 allows the user to either remove the guidewire and working catheter from the patient manually or to complete theprocedure manually.

In one embodiment, cassette 300 is a single-use or disposable cassettethat includes a use restriction element that acts to functionallydisable the cassette from being used for more than one catheterizationprocedure. In one embodiment, the use restriction element is a frangiblepiece located within one or more of the capstan sockets that preventscassette 300 from being remounted onto the capstans of motor drive base302 after it has been removed. In another embodiment, the userestriction element is an RFID tag that communicates with an RFIDreceiver indicating whether cassette 300 has previously been used. Inanother embodiment, the use restriction element includes a bar codeassociated with cassette 300 that must be scanned prior to use. If thebar code scanned is associated with a cassette that has already beenused, reuse of the cassette is prevented.

In a further embodiment the robotic catheter system makes use ofmagnetic interactions to enhance either the transport of a catheterdevice or the measurement of its motion as it is transported by a drivemechanism of the system. In one embodiment the robotic catheter system,such as that illustrated in FIG. 19, includes a first drive mechanism350 comprising a drive wheel 410 mounted on a hub 408 which interactswith the first catheter device to cause it to move parallel to its axis,a first encoder assembly 406 which detects the motion of the firstcatheter device with this encoder assembly including a wheel 442,mounted on a hub 438, that is driven by interaction with the firstcatheter device, a second drive mechanism 352 comprising a drive wheel458 mounted on a hub 456 wheel which interacts with the second catheterdevice to cause it to move parallel to its axis and a second encoderassembly 454 which detects the motion of the second catheter device withthis encoder assembly including a wheel 466, mounted on a hub 464, thatis driven by interaction with the first catheter device. One of thesefour wheels has a magnetic interaction with the catheter device withwhich it interacts. The magnetic interaction may be provided by amagnetic field generated by one of the drive or encoder wheels. Thewheel generating the magnetic field may do so by being associated with apermanent magnet or an energized electromagnetic coil. The magnet orcoil may be part of the wheel or the hub on which it is mounted.

In the embodiment in which it is one of the drive wheels which has amagnetic interaction, the interaction is expected to increase thefraction between the drive wheel and the catheter device which itdrives. It is expected that this will mean that thinner lower tolerancewheels could be used. It is also expected that there would be lessslippage between the driven catheter device and its drive wheel so thatthere would be a closer correlation between the rotation of the drivewheel and the axial motion of the device. In the embodiment in which thedrive wheel is the one which drives the second catheter device andrelies on an idler wheel which is part of an encoder assembly for pinchforce, it is expected that the pinch force could be low enough thatthere would be separation between the drive wheel and the idler wheel.It is further expected that the improved traction would allow the use oflower pinch forces such that the resistance to rotation of the catheterdevice about its axis would be reduced. This in turn would allow thetransmission of higher torsional forces to the catheter device.

In the embodiment in which it is a wheel of an encoder assembly whichhas a magnetic interaction, the interaction is expected to increase thetraction between the wheel and the catheter device which it ismonitoring. This should allow a reduction of the pinch force betweenthis wheel and either the idler wheel or drive wheel with which it ispaired. In the former case this should lead to a reduction in theresistance to axial motion of the catheter device and in both cases theresistance to rotation of the catheter device about its axis. It isexpected that in the case of the encoder assembly wheel normally pairedwith an idler wheel that the idler wheel could be eliminated.

In this regard, for ease of description the term catheter device is usedin an expansive sense to encompass not only guide catheters and workingcatheters, such as those used to deploy angioplasty balloons and stents,but also the guide wires used in conjunction with the guide and workingcatheters regardless of the fact that guide wires are clearly not a typeof catheter. Guide wires are typically made of highly worked stainlesssteel or other materials subject to the actions of a magnet, i.e.capable of being readily magnetized. Guide and working catheters mayneed to be modified to enable them to participate in a magneticinteraction. For instance, the plastics of which such catheters are madecould be embedded with magnetic of magnetizable particles or specialpolymers that display magnetic properties could be utilized in theconstruction of these catheters.

In one embodiment the movement of a catheter device is monitored by amagnetic interaction between the catheter device and an encoderassembly. The encoder assembly may be a structure that generates amagnetic field that interacts with the catheter device. In oneembodiment the movement of the catheter device would cause thisstructure to be moved or to be strained and this movement or straincould be measured and correlated to the movement of the catheter device.Referring to FIG. 29C a wheel movement gauge 630 comprises a wheel 632that rotates about an axis 634 and carries embedded magnets 636. Theguide wire 301 is magnetically responsive such that as it moves alongits axis it interacts with the magnets 636 and causes the wheel 632 torotate about its axis 634. This rotation is sensed by a Hall effectsensor 618. The axis 634 is located a sufficient distance above the baseplate 318 to allow the wheel 632 to freely rotate. The wheel movementgauge 630 may be located in the same general region as the mechanicalencoder assembly roller 466 shown in FIG. 19. One approach is to havethe structure configured as a beam with a permanent magnet or anenergized electromagnet coil disposed at one end and to have this endadjacent to the path of the catheter device. In one embodiment the beamis provided with a pivot point so that it can rotate in the direction ofaxial motion of the catheter device. Referring to FIG. 29B a pivotingbeam movement gauge 620 comprises a pivoting beam 616 that has a pivotpoint 617 intermediate its ends. A magnet 612 is affixed to the top endof pivot beam 616 proximate guide wire 301 and a magnet 614 is affixedto the bottom end of pivot beam 616 distal from guide wire 301. Theguide wire 301 is magnetically responsive such that as it moves alongits axis it interacts with the magnet 602 and causes the beam 616 torotate about its pivot point 617. This rotation is sensed by a Halleffect sensor 618. The pivot point 617 is located a sufficient distanceabove the base plate 318 to allow the pivoting beam 616 to freelyrotate. The pivoting beam movement gauge may be located in the samegeneral region as the mechanical encoder assembly roller 466 shown inFIG. 19. In another embodiment the beam is fixed so that it is not ableto move without deformation but it is deflectable. The elasticdeformation or strain that it suffers as a result of the magneticinteraction can then be used as a measure of the movement of thecatheter device. Referring to FIG. 29A a beam flexure movement gauge 600comprises a flexure beam 604 that is anchored at one end to the baseplate 318. A magnet 602 is affixed to the other end of the beam 604 anda strain gauge 606 is affixed intermediate to the ends. The guide wire301 is magnetically responsive such that as it moves along its axis itinteracts with the magnet 602 and causes the beam 604 to deflect. Thebeam flexure movement gauge may be located in the same general region asthe mechanical encoder assembly roller 466 shown in FIG. 19.

In one embodiment the path of a second catheter device is affected by amagnetic interaction after it exits its drive wheel when moving in theforward direction in a manner which reduces the frictional resistance toits forward axial motion. Referring to FIG. 17, in some robotic cathetersystems a second catheter device, such as the working catheter 303illustrated in FIG. 18, is caused to follow an arcurate path such as366. The resistance which such a second catheter device experiences inmoving forward could be reduced if its path were affected such that itwas moved away from the wall of the arcurate channel, such as 366,having the longer arc. This is expected to be the result of placingpermanent magnets or energized electromagnet coils generating asufficient magnetic field adjacent to the wall of the arcuate channelhaving the shorter arc. Of course, as discussed above, this requires asecond catheter device which is subject to magnetic interaction.Referring to FIG. 30, a channel 323 follow the arcurate path 366 shownin FIG. 17 and has a side wall 325 along its shorter arc and a side wall327 along its longer arc. Side wall 325 is provide with an array ofmagnets 640 which lie below the top deck 354 of the axial drive assembly324. Referring to FIG. 31 a working catheter 303 passes drive wheel 458and encoder assembly roller 458 and passes into channel 323. The sidewall 325 has been provided with an array of magnets 640 which interactwith the working catheter 303 such that working catheter 303 isdeflected toward side wall 325. Working catheter 303 is constructed tobe responsive to a magnetic force.

Further modifications and alternative embodiments of various aspects ofthe invention will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. Any of thefeatures, elements, or components of any of the exemplary embodimentsdiscussed above may be used alone or in combination with any of thefeatures, elements, or components of any of the other embodimentsdiscussed above. It is to be understood that the forms of the inventionshown and described herein are to be taken as presently preferredembodiments. Elements and materials may be substituted for thoseillustrated and described herein, parts and processes may be reversed,and certain features of the invention may be utilized independently, allas would be apparent to one skilled in the art having the benefit ofthis description of the invention. Changes may be made in the elementsdescribed herein without departing form the spirit and scope of theinvention as described in the following claims.

What is claimed is:
 1. A robotic catheter system, the system comprising:a first drive mechanism comprising a drive wheel mounted on a hub whichinteracts with the first catheter device to cause the device to movealong its axis; a first encoder assembly which detects the motion of thefirst catheter device, this encoder assembly including a wheel, mountedon a hub, that is driven by interaction with the first catheter device;a second drive mechanism comprising a drive wheel, mounted on a hub,which interacts with the second catheter device to cause the device tomove along its axis; a second encoder assembly which detects the motionof the second catheter device, this encoder assembly including a wheelmounted on a hub that is driven by interaction with the first catheterdevice; wherein at least one of the four wheels has a magneticinteraction with the catheter device with which it interacts.
 2. Therobotic catheter system of claim 1 wherein at least one of the fourwheels generates a magnetic field.
 3. The robotic catheter system ofclaim 2 wherein at least one of the magnetic fields is generated by oneor more permanent magnets which is part of a wheel, or the hub on whichit is mounted, which is generating a magnetic field.
 4. The roboticcatheter system of claim 2 wherein at least one of the magnetic fieldsis generated by one or more energized electromagnetic coils which arepart of a wheel, or the hub on which it is mounted, which is generatinga magnetic field.
 5. The robotic catheter system of claim 1 wherein thefirst catheter device is a guide wire and the second catheter device isa working catheter which deploys an angioplasty balloon or a stent.
 6. Arobotic catheter system, the system comprising: a first drive mechanismwhich interacts with a catheter device to cause the device to move alongits axis; a first encoder assembly which detects the motion of thecatheter device by a magnetic interaction with the catheter device. 7.The robotic catheter system of claim 6 wherein the encoder assemblygenerates a magnetic field.
 8. The robotic catheter system of claim 7wherein magnetic field is generated by one or more permanent magnetswhich is part of the encoder assembly which is generating a magneticfield.
 9. The robotic catheter system of claim 7 wherein the magneticfield is generated by one or more energized electromagnetic coils whichare part of the encoder assembly which is generating a magnetic field.10. The robotic catheter system of claim 6 wherein the encoder assemblyincludes a pivoted beam whose rotation about its pivot point isproportional to the speed and direction of the catheter device which itis monitoring.
 11. The robotic catheter system of claim 6 wherein theencoder assembly includes a fixed deflectable beam fixed at some pointabout its length, wherein the deflection of one of its ends about itspoint of fixation is proportional to the speed and direction of thecatheter device.
 12. The robotic catheter system of claim 6 wherein thecatheter device is a guide wire.
 13. A robotic catheter system, thesystem comprising: a first drive mechanism comprising a drive wheel,mounted on a hub, which interacts with the first catheter device tocause it to move along its axis; a first encoder assembly which detectsthe motion of the first catheter device; a second drive mechanismcomprising a drive wheel, mounted on a hub, which interacts with thesecond catheter device to cause the device to move along its axis; asecond encoder assembly which detects the motion of the second catheterdevice; an arcuate channel which guides the second catheter device afterits exit, when moving in a forward direction, from the second drivemechanism; wherein the second catheter device is drawn against the wallof the channel with the smaller arc by a magnetic interaction.
 14. Therobotic catheter system of claim 13 wherein a magnetic field isgenerated adjacent to the channel wall with the smaller arc.
 15. Therobotic catheter system of claim 14 wherein the magnetic field isgenerated by one or more permanent magnets placed adjacent to thechannel wall with the smaller arc.
 16. The robotic catheter system ofclaim 14 wherein the magnetic field is generated by one or moreenergized electromagnetic coils placed adjacent to the channel wall withthe smaller arc.
 17. The robotic catheter system of claim 13 wherein thefirst catheter device is a working catheter which deploys an angioplastyballoon or a stent and the second catheter device is a guide wire.
 18. Arobotic catheter system, the system comprising: a drive mechanismcomprising a drive wheel, mounted on a hub, which interacts with acatheter device to cause the device to move along its axis and in whichthe mechanism has a magnetic interaction with this catheter device. 19.The robotic catheter system of claim 18 wherein the drive wheel or itshub generates a magnetic field.
 20. The robotic catheter system of claim18 wherein the catheter device is a guide wire.